<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript" charset="utf-8">
        /**
         *定义一个单独的作用域
         */
        (function () {
            alert("我直接执行了！");
       })()
    </script>
</head>
<body>
</body>
</html>